High leakage reactance transformer



Patented Dec. 26, 1939 arse m PATENT OFFICE HIGH LEAKAGE REACTANOE TRANS- FORMER James A. Conistock, Cleveland, Ohio, asslgnor to The Acme Electric Manufacturing Company,

Cleveland, Ohio, a corporation of Ohio Application August 31, 1935, Serial No. 88,150

SClaims.

My invention relates to transformers and more particularly to high leakage reactance transformers.

An object of my invention is the provision of l a transformer adapted to energize an electrical load having a variable resistance which, when the transformer is connected in circuit relation with the electrical load, gives a relatively high initial voltage when the resistance of the elecl0 trical load is relatively high, and gives a relatively low operating voltage after the resistance of the electrical load decreases to a relatively low value.

Another object of my invention is to provide 16 for limiting and regulating the amount of flux which interlaces the secondary windings of the transformer in accordance with the current flowing through the said windings.

A still further object of my invention is to provide for by-passing a portion of the flux which interlaces the secondary windings, in accordance with the current flowing through the said windings.

It is also an object of my invention to provide,

in a high leakage reactance transformer, an internal T-shaped shunt for by-passing a portion of the flux that interlaces the secondary windings.

It is also an object of my invention to provide for limiting the short circuited current of either one of two secondary windings, while at the same time keeping the other secondary windings in an operative condition.

Other objects and a fuller understanding of my invention may be had by referring to the following description and claims, taken in combina- 1 tion with the accompanying drawing, in which:

Figure 1 represents a diagrammatic form of a transformer, embodying the features of my ino vention;

Figure 2 represents a transformer similar to that'illustrated in Figure 1, but illustrating a modified form of the magnetic shunt means; and

Figure 3 illustrates a transformer of the form shown in Figure l, but with a still further modifled form of magnetic shunt means.

with reference to Figure 1 my transformer comprises, in general, magnetic core means indicated generally by the reference character ill,

a primary winding P I, twosecondary windings SI and S2, and an internal T-shaped magnetic shunt comprising two parts If and I2, which function to limit the secondary current.

As illustrated, the magnetic core means III is I substantially rectangular and may be constructed of two sets of L-shaped stack of laminations i3 and Il properly abutted or joined together by suitable rivets in the usual manner of constructing magnetic cores for transformers. The primary winding PI is mounted upon the left hand 6 side I! of the magnetic core, and the second windings SI and S! are mounted upon the opposite side it of the magnetic core portion. As shown, the T-shaped magnetic shunt comprises two parts II and If. The right hand end of the 10 part II abuts the inner surface of the side It intermediate the two secondary windings SI and S2 indicated by the reference character ll, and the left hand end of the part I I is V-shaped and arranged to fit into a complementary V-shaped 15 notch provided in the right hand edge of the part ii. In order that the shunt may have a higher reluctance than the magnetic core portion under the secondary-windings, I provide for making suitable air gaps l8, l9, and 20. The 20 air gap i8 is between the left hand V-shaped end of the part II and the V-shaped notch cut in the part l2; the air gap 19 is between the lower end of the part I! and the inside surface of the lower side of the magnetic core means; and the an air gap 20, is between the upper end of the part If and the inside surface of the upper side of the magnetic core means.

In Figure 1, I have illustrated my transformer as being connected in circuit relation with two gaseous tubes 2| and 22. The left-hand electrode 23 of the gaseous tube II is connected to the secondary winding Si, and the left-hand electrode 24 of-the gaseous tube 22 is connected to the secondary winding S2. The adjacent ends of the secondary windings SI and S2 are connected to the common point 25.

The common point 25 is, in turn, connected to the ground 26 and to a common point 21. The right-hand ends of the gaseous tubes 2| and 22 40 are also connected to the ground 26.

The operation of this form of my invention'is such that the magnetic shunt functions to bypass a portion of the primary flux in orderto limit the secondary current to a safe value. Thus, 46 by reason of the air gaps, when the primary winding PI is first energized, substantially all of the primary flux flows through the secondary winding SI and S2 with very little flux flowing through the part l2 of the magnetic shunt. This 60 means that there is induced in the first instance in the secondary windings SI and S2 a relatively high voltage which ionizes the gas and thus illuminates the two gaseous tubes. Just as soon as the tubes are ionized and the secondary current 86 tends to rise, there is established a secondary opposing flux which constrains the primary flux to pass through the part I2 of the magnetic shunt. As a result, the secondary current in the secondary windings SI and S2 is limited to a safe value. The degree to which the secondary current is limited depends on the reluctance of the magnetic shunt and upon the design and proportions of the various other co-acting parts of the transformer.

The result and effect of the two magnetic shunts is such that, after the gas of the gaseous tube is ionized, the relatively high initial secondary voltage is immediately and automaticall reduced to its normal operating value.

The part II of the magnetic shunt comes into play when the load upon the secondary windings SI and S2 are unequal or when either one of the two secondary windingsSI and S2 is short circuited. Thus, for instance, if the secondary winding SI is short circuited, as by the occurrence of a ground at the electrode 23, the secondary current in the winding SI will tend to immediately rise and establish a relatively high opposing flux and cause the primary flux to flow through the upper part I2 and the horizontal part II of the magnetic shunt and interlace only the secondary winding S2 and keep it in operation for illuminating the gaseous tube 22 to which it is connected. This means that the gaseous tube 22 continues to operate even though the secondary winding SI is short circuited. On the other hand, should a ground occur at the electrode 22 and the secondary winding S2 be short circuited, the primary flux then is constrained to flow through the lower part I2 and the horizontal part II of the magnetic shunt and interlace the secondary winding SI, and keep it in operation to energize the gaseous tube 2I to which it is connected. As a result, the short circuited current of either one of the two secondary windings SI and S2 is maintained at a safe value while the other winding is kept in normal operation. The action of the shunt is the same but of a smaller degree when the electric load upon the secondary windings is unequal as will be the case when the operating characteristics of the gaseous tube are not the same. Under cases of an unequal load on the secondary windings SI and S2, the magnetic shunt tends to re-balance the electric load by by-passing a portion of the flux. This re-balancing action not only gives improved operation but also makes it possible to operate the gaseous tube of a given length and of a given characteristic at a lower "flickering voltage (that is, the voltage at which a given tube just begins to flicker) than at which the tube could be operated with a transformer having no re-balancing action.

In Figure 2, I show a transformer similar in construction to that shown in Figure 5 except that the T-shaped magnetic shunt is constructed of two L-shaped laminations 30 and 3| having their back adges abutted together as indicated by the reference character 32. In Figure 3,1 show an arrangement 01' a transformer similar to that shown in Figures 1 and 2 except that the magnetic shunt is constructed of one integral piece 33. It is to be noted, however, that the operation of the transformers shown inFigures 2 and 3 are substantially the same as that just described with reference to Figure 1.

In all of'the illustrations of my transformer, it is pointed out that the magnetic shunts function to limit the value of the secondary current by by-passing a portion of the primary fiux.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

I claim:

1. A transformer that is adapted to energize an electrical load having a variable resistance comprising, in combination, magnetic core means having four sides, a primary winding disposed to surround one of the sides,-two spaced secondary windings disposed to surround the side that is opposite the side which the primary winding surrounds, and a T-shaped magnetic shunt having the base of the said shunt positioned in magnetic relation with the magnetic core means between the two spaced secondary windings and having the ends of the arms of the said shunt positioned respectively in magnetic relation with the other i two sides of the magnetic core means.

2. A transformer that is adapted to energize an electrical load having a variable resistance comprising, in combination, magnetic core means having four sides, a primary winding disposed to surround one of the sides, two spaced secondary windings, disposed to surround the side that is opposite the side which the primary winding surrounds, and a T-shaped magnetic shunt having the base of the said shunt positioned in magnetic relation with the magnetic core means between the two spaced secondary windings and having each of the ends of the arms of the said shunt positioned respectively in magnetic relation with the other two sides of the magnetic core means, said T-shaped magnetic shunt being constructed of two portions.

3. A transformer that is adapted to energize an electrical load having a variable resistance comprising, in combination, magnetic core means having four sides, a primary winding disposed to surround one of the sides, two space secondary windings disposed to surround the side that is opposite the side which the primary winding surrounds, and a magnetic shunt having three end portions, one of said end portions being positioned in magnetic relation with the magnetic core means between the two spaced secondary windings, and the other two end portions being positioned respectively in magnetic relation with the other two sides of the magnetic core means.

JALIES A. COMSTOCK. 66 

